The seismic safety evaluation of the dam is performed based on either dam strength failure or dam abutment instability failure according to the traditional deterministic methods and concepts in the current code. However, these two failure modes are interactive and inseparable, considering only one failure mode under a strong earthquake fails to fully reflect the actual seismic performance of high arch dams. To develop a more realistic seismic safety evaluation framework for high arch dams, this paper constructs a finite element analysis model that considers the coupling of dam strength failure and dam abutment instability failure. The nonlinear dynamic response analysis of the high arch dam-foundation coupling system is conducted using the seismic overload analysis method. Different performance evaluation indexes, such as damage depth-thickness ratio, sliding area ratio, and the residual displacement of the dam crest relative to the dam bottom in the stream direction, are proposed. The performance evaluation criteria and ultimate seismic capacity are defined and quantitatively assessed. The results indicate that 2.0 times the horizontal PGA can be considered the ultimate seismic capacity of the high arch dam-foundation coupling system, providing a reliable scientific basis for seismic safety evaluation of high arch dams.